A linear actuator is an actuator that creates motion in a straight line, in contrast to the circular motion of a conventional electric motor. Linear actuators are widely used within the area of adjustable furniture, such as beds, chairs, or tables, where they may be used for adjusting the position of adjustable furniture, such as the lifting and reclining of motion chairs, the height of a table, or the position of the mattress surface of a bed. The actuator is typically comprised of an electric motor drive assembly that drives a threaded spindle. The spindle is retained within a rigid arm, and the electric motor drive assembly is attached to the rigid arm with a plurality of threaded fasteners. A pusher block is threaded onto the spindle and is secured in linear recesses within the arm. As the electric motor drive assembly turns the spindle, the pusher block moves from one end of the arm to the other end. The direction of movement is determined by the direction of the spindle's rotation.
One end of the prior art actuators may be secured to the adjustable furniture by a rear mounting bracket. The actuators are also attached to the furniture by a pair of levers or linkages. One end of the respective linkages is secured to the pusher block with a plurality of threaded fasteners. The other end of the respective linkages communicates with the furniture. Movement of the pusher block moves the linkages and adjusts the position of the furniture.
The prior art linear actuators are costly to manufacture. Connection of the electric motor drive assembly to the rigid arm using threaded fasteners is disadvantageous because it is a time-consuming and complicated method of assembling the actuators. The prior art actuators are also difficult to mount on adjustable furniture. Use of threaded fasteners on the pusher block makes it difficult for assembly line workers to align the furniture so that the levers line up with threaded apertures in the pusher block.
Accordingly, there is a need for a linear actuator that can be quickly assembled and mounted onto adjustable furniture.